Interferometer Parameters
Old parameter sets (before 2010)
(Classical-noise parameters are here) Parameter LCGT VRSE-D1 LCGT VRSE-B units Laser source Wave length 1064 nm Initial Laser Power 150 W Injecting Laser Power into IFO 78.48 (in total), 75 (carrier) W Modulation depth 0.3 for both RF freq 1 11.25 (PM) MHz RF freq 2 45.00 (PM) MHz MC1 length 13.324109 m MC2 length 13.324109 m MC1 FSR MHz MC2 FSR MHz MC1 Finesse MHz MC2 Finesse MHz Parameters of interferometer Arm cavity Finesse Arm power gain Arm power(single) MW Arm cavity FSR MHz Arm cavity cut-off frequency Hz PR gain PRC power on BS W PRC cavity FSR MHz PR cavity cut-off frequency Hz PR-Arm cut-off frequency Hz SR gain Signal band Hz MICH contrast Other losses in PRC Other losses in SRC Cavity Length Arm cavity length 3006.69 m PR cavity length 73.2826 m Asymmetry length 3.33103 m BS-FM length 25 m SR cavity length 73.2826 m SRC detuning phase 0.05934 = 3.4 degree 0 rad Mirror geometries or mechanical properties EM mass 30 kg FM mass 30 kg PRM mass kg SRM mass kg BS mass kg EM ROC 7113.900 m FM ROC 7113.900 m FM AR ROC m PRM ROC m SRM ROC m BS ROC Infinity m EM thickness 15 cm FM thickness 15 cm PRM thickness cm SRM thickness cm BS thickness cm Mirror optical properties EM Reflectivity 0.999945 FM Reflectivity 0.996 PRM Reflectivity 0.9 SRM Reflectivity 0.8464 = 0.92^2 BS Reflectivity 0.5 HR Coating Loss of EM, FM, PRM and SRM 45e-6 BS Loss 100e-6 Transmissivity 1 - R - Loss AR Transmissivity 0.999 AR Coating Loss Bulk loss (absorption) (large optics: ???FM, EM) ppm/cm Bulk loss (absorption) (small optics: ???) ppm/cm Output Mode Cleaner OMC length 1.5 m OMC Finesse 2000 OMC input/output mirror reflectivity OMC end mirror reflectivity OMC MC FSR ??? MHz Control Bandwidth Quantum efficiency 0.9 CARM control band width 30k Hz DARM control band width 200 Hz PRC control band width 50 Hz MICH control band width 50 Hz SRC control band width 50 Hz Feed-Forward gain -0.97 1/(1-0.97) = 30
TBD
TBD
TBD
TBD
TBD
TBD
Not defined
Not defined
Not defined
1000e-6
20
2.5
To be designed
To be designed
To do list to define parameters for 2009
Reference
Length Sensing Scheme Review by Somiya (Japanese) lcgtrse.pdf
Length Sensing Scheme Review for advLIGO by Somiya AdvLIGO-LSCv4.pdf